Hybrid Automatic Repeat Request (HARQ) is commonly used in modern communications systems on top of the physic layer in order to mitigate errors that occur during transmission of data. For instance, the High Speed Downlink Packet Access for Wideband Code Division Multiple Access (WCDMA) and Long Term Evolution (LTE) networks use HARQ at the physical layer to mitigate errors that occur during transmission of data. In general, in HARQ systems, an incorrectly received data block (e.g., a packet) is retransmitted and all transmissions for the data block are jointly decoded. More specifically, in a HARQ system, a transmitter sends a transmission of data to a receiver. If the receiver is unable to successfully decode the transmission, the receiver sends a negative acknowledgement (NACK) to the transmitter over a reverse control channel. In response, the transmitter performs a HARQ retransmission. For type-I HARQ, which is sometimes referred to as Chase Combining (CC), the retransmission comprises the same bits sent in the initial transmission. For type-II HARQ, sometimes referred to as HARQ with incremental redundancy, new bits are added to the retransmission. This process is repeated until the receiver has successfully decoded the transmission or a maximum allowable number of retransmissions have been performed.
Traditionally, HARQ systems are configured such that most HARQ-enabled transmissions are successfully decoded by the receiver on the first transmission iteration without any retransmissions. The inventors have found that always targeting successful reception of HARQ-enabled transmissions on the first transmission iteration does not utilize the full capacity of the HARQ feature particularly under certain channel conditions. As such, the present disclosure relates to systems and methods that utilize HARQ retransmissions to improve throughput in wireless systems.